Prolonged myocardial ischemia after intravenous dipyridamole thallium imaging.

Intravenous dipyridamole thallium imaging is reported to be a safe test with minimal side effects. It has been proposed by some that the test simply dilates the coronary vessels without actually producing myocardial ischemia. In this report, we describe a patient who, following intravenous dipyridamole thallium imaging, developed severe myocardial ischemia which persisted for 90 minutes, requiring emergency coronary angioplasty to alleviate the ischemic insult. Sequential electrocardiograms and cardiac isoenzyme levels following coronary angioplasty were within normal limits. Thus, severe myocardial ischemia following intravenous dipyridamole testing can occur and emphasizes the importance of careful monitoring of these patients, particularly when the pretest risk of coronary disease is high.